1. Field of the Invention
The present invention relates to an image communicating apparatus.
2. Description of the Related Art
In a facsimile communication, in the case in which the number of dots between EOL (End of line) codes added to an end of a transmission line at a receiver side is not coincident with the number of dots which is determined by T.4 recommended in ITU-T to be a telecommunication standardization sector of ITU (International Telecommunication Union), a decision of a transmission error line is made.
More specifically, received image information is composite and the number of dots between the EOL codes is then counted on the receiver side. If the number of transmission lines in which the count value is not coincident with the number of dots determined by the T.4 exceeds a preset threshold, an RTP signal (a retraining positive signal) or an RTN (a retraining negative signal) is transmitted as a transmission line error to a transmitter side.
The RTP signal indicates that a message (image information) is completely received, and furthermore, represents that a subsequent message communication may be continued after a transmission/receipt of a training or synchronizing signal and a CFR signal (a receiving standard confirming signal).
Moreover, the RTN signal indicates that the message is not completely received but the subsequent message can be received if the training or synchronizing signal is retransmitted.
According to the technique, even if data to be transmitted are lost or a data change is caused due to a short break of a power supply or a noise, thus, it is detected as a deviation of the number of dots between the EOLs. Consequently, it is possible to reliably detect the transmission line error on a receiver side.
Even if the data loss or data change is caused continuously for a certain period so that data corresponding to several lines cannot be received normally, moreover, a probability that start and end parts of a data abnormality will be exactly applied to a break of the line is low on a probability theory basis. Also in this case, therefore, it is possible to make a detection of at least an error of one or two lines in front and rear parts.
In a facsimile communication using an IP (Internet Protocol) network having a T.38 method recommended in the ITU-T, a method of packeting data every line or several lines and transferring the packet in a non-ECM (Error Correction Mode) communication is a mainstream.
In the packet transferring method, data are lost or cancelled on a packet unit over the IP network in many cases. If the packet is lost during a receipt of image information, data are clearly missing exactly in a break of a line. Even if the data are lost, therefore, it is impossible to carry out counting as a transmission error line in the method.
As a result, there is a possibility that “normal end” might be obtained as a result of the receipt and a lack caused in an information transfer between users cannot be recognized, resulting in troubles even if a received image has a lack and is thus short.